Even though there was no visible change, I still have no idea why it vanished. However, a comparable function can be utilized in its stead.
Solution can be found here https://pandasdoitbetter.blogspot.com/2023/12/lametric-time-mystrom.html
I also don't know why it disappeared when there was no apparent update. But you can use another similar function to replace it.
Rene
Why ist the mystrom app gone? This app worked fine! I need it to be able to measure my current solar production.